Protective apparatus



y 6, 1950 E. H. YONKERS 2,508,055

PROTECTIVE APPARATUS Filed Jan. 16, 1946 5 Sheets-Sheet 1 IN V EN TOR.

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PROTECTIVE APPARATUS Filed Jan. 16, 1946 5 Sheets-Sheet 2 INVENTOR.mam/20 hf VON/(Z95 y 1950 E. H. YONKERS 2,508,055

[N V EN TOR.

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PROTECTIVE APPARATUS Filed Jan. 16, 1946 5 Sheets-Sheet 5 I N V EN TOR.Evil/4P0 H. VON/(E25 BY mwea fiw ww QTTOENEYS Patented May 16 1950UNITED STATES PATENT OFFICE "PROTECTIVE APPARATUS Edward H. Yonkers,Chicago, 111., assignor to Joslyn, Manufacturing and Supply Company,

Chicago, 111., a corporation of Illinois Application January 16, 1946,Serial No..641,605

v 12Claims.

1 ;-The present invention relates to protective apparatus and more;particularly to improvements 1 in apparatus for protecting a polesupported electrical distribution transformer and for disconnecting, thetransformer fromits current supply line when a fault occurs therein.

Apparatus for the purpose described is in r .certainlinstallationsmounted directly ,upon the .housing or tank of, thetransformer which itis :used-to protectand .conventionallyincludes entirely independentlightning arrester and fused cutout units for protecting the transformerprimary winding .againstdamage occasioned by .';lightning surges and.overload conditions, respec- "tively. In commercial practice fewattempts ":have' been 'made to provide asingle unitary device forproviding complete transformer protection against dangerous-.overvoltageand overloads while at the same time providing the usual In none oftecting unit. -The problem of using these facilities-for supporting thep'rotectiveunit is complicated somewhat-by the fact that many trans-formers must be adapted' forpolemounting in any one of two-ormorepositions in order to 4 facilitate connection to the transformer second---aryterminals, which means in turn that the A components of theprotective unit must be sewn- *structed as to permit partial supportthereof -upon any one of-two or moretank'brackets.

' It is anobject of the present invention, there- -for'e, to provideimproved apparatus of the character described which is so constructedthat all of' theabovementioried problems are obviated.

It isanother object of thei'nvention to provide for use in acombination"arrestor-cutout unit, animp'roved fused-cutout which may be"easily and quiekly" adapted for mounting upon the availablesupportingdacilities of a conven- *"'tional electrical "distributiontransformer *either of two different positions.

According to a-furtherand more specific ob- *"ject of the invention;- animproved and exceeding 1y simple subassembly is provided for pivotallysupporting a fuse tube upon a transformer bushing stud or the like forswinging movement between open and closed circuit positions, for lookingthe fuse tube against removal from the stud except when rotated to itsfull open circuit-position and for automatically swinging the tube toits open circuit position incident to fuse rupture within the tube.

Inaccordance with still another object of the invention, exceedinglysimple facilities are embodied in the described sub-assembly forsupporting the fuse tube in either of two positions angularly displacedabout the longitudinal axis of the fuse tube, thereb to adapt the fusetube assembly for cooperationlwitha stationary ter- .minal supported ineither of two positions relative to. the point of pivotal support of thetube.

It is a-further objectlof' the invention to pro- .vide. in protectiveapparatus of the character described, improved .contact. and fuseconductor extracting facilities for normally maintaining anunbrokencircuit through therfused current path v.of thecutout and foreffecting. fuse conductor extraction and providing a line disconnectinga break in the circuit incident to fuse. rupture.

Inaccordance with. still another object of the invention the improvedfuse conductor'extracting facilitiesare arranged to assist a in swingingthe fuse tube to itsvopen circuit. setting incident to fuserupture'within-the tube, without impairing thespeed offuse conductorextraction.

The-invention.-both--asto -its organization and methodof-operation,together with further objectsand advantages thereof, will best beunderstood by 'reference to the followingspecification taken inconnection with- -the accompanying drawings, in which:

his a ton perspective-view of a conventional electrical-= distributiontransformer equipped with the'present improved. protective apparatus;

Fig. 2 is a perspective'view similar to Fig; 1.

but illustrating the parts of'the' protective appa 'atus in changedpositions;

'Fig. 3 is top plan viewpartially in section illustrating furtherdetails of the fused cutout formin a part of the protective apparatusillustrated in- Figs. 1 and 2;

Figs. 4 and dare fragmentary views similar to Fig. 3, but illustratingthe parts of the fused cutout in changed positions:

6 is aside view partiallyrin section illustrating the 'subassembly'provided for pivotally supporting the fuse tube assembly of the cutoutupon the bushing stud of the transformer;

Fig. 7 is an explosion view in perspective illustrating the details ofthe facilities provided for rotatably supporting the fuse tube in eitherof two positions upon the supporting subassembly illustrated in Fig. 6.

Fig. 8 is an explosion view illustrating in perspective the cooperativeparts of the stationary terminal assembly with which the swing endcontact of the fuse tube assembly is engageable, and the contact part ofthe fuse extracting member which is engageable with this terminalassembly and is embodied in the fuse tube assembly;

Fig. 9 is a side view illustrating the bracket means provided foradjustably supporting the arrestor insulator of the protective apparatusin any desired position upon either of the twosets of transformersupporting brackets;

Fig. 19 is a fragmentary perspective view illustrating further detailsof the bracket means shown in Fig. 9;

Fig. 11 is a sectional view taken along the lines ll--Il in Fig. 6; and

Fig. 12 is an explosion view in perspective of the fuse conductor tieassembly forming a part of the fuse extracting mechanism.

Referring now to the drawings, and more particularly to Figs. 1 and 2thereof, the present improved protective apparatus is there illustratedas comprising a combination lightning arrestor and fused cutout unitsupported by the existing supporting facilities of a standard electricaldistribution transformer l0. Specifically, this transformer comprisestwo sets of supporting brackets l i and I2 which are arranged inspacedapart relationship around the sides of the transformer tank toproject radially therefrom, are fixedly mounted upon the transformertank and are adapted for alternative use in supporting the tank upon asupporting pole or similar supporting structure. The purpose ofproviding two sets of brackets is to facilitate connection of secondarycircuit conductors to the secondary terminals of the transformer (notshown), which are brought out through a terminal block disposed alongthe hidden side of the transformer tank approximately midway between thebrackets. As best shown in Figs. 1, 2 and 6 of the drawings, thetransformer is also equipped with the usual bushing insulator l3 whichprojects upwardly from the top of the transformer tank and servesinsulatingly to support the usual terminal stud l8. This stud and theunused set of supporting brackets H and i2, are employed to support allparts of the present improved combination arrestor-cutout unit.

In brief, this unit comprises a self-contained lightning arrestor Ma,the parts of which are housed within a petticoated insulator I4, a fusetube assembly l5, a terminal subassembly [6 for supporting the fuse tubeassembly for pivotal swinging movement about the long axis of the studl8 and a stationary terminal assembly H with which the contract providedat the swing end of the fuse tube assembly I is latchingly engageable.More specifically, the electrode structure of the lightning arrestor Mashown in dash lines in Fig. 9 of the drawings is housed within a cavityextending upward from the lower end of the insulator l4. Preferably,this arrestor is of the improved expulsion type disclosed and claimed inPatent No. 2,164,720 granted July 1939, to Ralph R. Pittman. Among otherelements it comprises a pair of spaced electrodes, one of which isconnected to a conductive rod 58 extending through the insulator id tothe upper end thereof to support the terminal assembly H, and the otherof which is connected to a gap electrode [41).

For the purpose of adjustably supporting the insulator i4 and associatedparts in a desired vertical and horizontal position upon either of thetwo sets of radially extending brackets ll and i2, two cooperatingbrackets 69 and i0 are provided. Specifically, the bracket 69 is ofsubstantially U-shaped configuration, having legs 69a which are adaptedclampingly to embrace the edges of the suppprting bracket ii, forexample, and are slotted as indicated at 690 to receive a clamping bolt13. With this construction, the bracket 69 may be supported upon thesupporting brackets H in a variety of laterally displaced positions bysliding the legs 69a thereof along the brackets H and sliding the bolt'53 along the slots 690 to occupy a position mid-way between thebrackets H. Further, by setting up the nut 13a on the bolt 13, thebracket 69 may be fixedly mounted upon the brackets il in any positionto which it is adjusted. The second bracket 10 is of L-shapedconfiguration, being provided with a half-collar end 13 cooperable witha clamping half-collar H and clamping screws 12 to embrace and rigidlysupport the insulator 14 about one of its petticoat corrugations. Thevertical leg of the bracket 10 is equipped with side flanges lob alongopposite edges thereof to provide a channel within which the verticalbase leg 6% of the bracket 69 may be received. This leg of the bracket69 is suitably slotted along its length to receive a clamping bolt M,thereby to provide for vertical adjustment of the bracket It and theinsulator l4 relative to the top of the tank 10. To extend this range ofvertical adjustment, the upper leg 69a is provided with an upwardlyextending U-shaped portion 69d. With this structure, the bracket 10 maywithin limits be adjusted to any desired vertical position and rigidlyclamped in the selected position. Further, the flanges lllb, in engagingthe edges of the bracket leg 69?), posi tively prevent rotation of thebracket 18 about the bolt 14. To provide an isolating gap in series withthe gap of the arrestor Ma between the conductive rod 58 and thetransformer tank, i. e. ground, the gap electrode Mb is positioned inspaced relationship to the bracket 10. An isolating gap l lc,appropriately designed as to length to prevent system current leakage,is thus provided in the protective path between the terminal assembly I!and the grounded transformer tank.

As indicated above, the terminal subassembly it is provided to act as apivotal support for the fuse tube assembly l5. Briefly, and as bestshown in Fig. 6 of the drawings this subassembly comprises a conductiveL-bracket l9 fixedly mounted by means of a bolt 20 upon the upper end ofthe stud l8, and in turn fixedly mounting a supporting stud 2i which isemployed adjustably to support the fuse tube assembly pivot stud 25 andits supporting base 22. More specifically, the stud 2| includes a baseportion Zla extending through and fixedly connected to the horizontalleg of the bracket l9, and a neck portion 2 lb tapering upwardly fromits lower end to its upper end which acts as a pivotal support for thebase 22 and pivot stud 25. The stud 25 is fixedly mounted upon the base22 to project upwardly therefrom, and along the bottom of this 'at'theupper side thereof.

base there is provided a half-collar portion 122a having a half-circularclamping surface suitably inclined to'the verticalto-mate with theflared neck-2 lb of the stud '2 l -A half-collarclamping ring 28 alsohaving an inclined half-circular "clamping sur'face-cooperable withthefiared neck s'iredangular setting-about the longitudinal axis nf thestuds "2| and' 25. Protection-against birds faulting the bushing studlB-to the transformer "tank isobtained by "enclosing the stud I 8 with acylindrical insulating member 29, the lower edgeof which-rests upon thetop of the insulator "Hand the upperedge of which supports aninsulating'disc "28. This disc is centrally apertured to receive thestud 2i and engages the base 22 Preferably,-the parts 28 and 29 areformed from a-suitable 'molded "insulatingmaterial such, for-example, asBake- *lite.

For the purpose of swinging the fuse tube "assembly "IE to its opencircuit'setting incident "to'fuse rupture and the additional purpose oflocking this assembly against detachment from the pivot stud 25 so longas it occupies any setting other than Y its open circuit setting, acombination biasing and locking'spring 26 is provided. "This spring ispreferably of multi-ply construc- "tion, isof U-shaped configuration andcomprises two legs zta-and 25b. The leg 25a is fixedly mounted upon an Lbracket 221) formed integral with the base 22 'and'extending laterallytherefrom. The vertical part of this 'bracketis recessed 'as indicatedat 220 to provide side flanges em- "bracing the edges of the "spring leg26a, "anda bolt 21 is employed fixedly 'to clamp thisspring leg to thebracket.

As best 'shown'in Figs. '1, 2 and "3 of the drawings,"the fusetubeassembly'l5 comprises a fuse tube "30,.a pivot element-35 adapted'fordetach- .able pivotal support by the pivot stud 25, a supporting arm :58and fuse conductor extracting means in the form of a resilient wiremember "45 pivotally carried by the arm "43 at the extended end of thisarm and provided with combination biasing and contact parts "54'latchingly engageable with the contact elements of the terminalassembly 'l'i. More particularly, and as best illustrated in Fig.7 ofthe drawings, the pivot element 35 comprises a tubular part 36 [having acentral bore 36a'for receiving the pivot .stud25, afuse tube supportingsocket3'l, a cammingpart '38 disposed along the base of the supportingpart 3 6, and a loop 39 adapted to receive the hook end of a switchstick to provide for switch stick manipulation of the fuse tubeassembly. The 1001139 of this element extends outwardly and overhangsthe fuse tube socket 31 in order that the assembly I 5 may be properly'balanced at the end of a switch stick when suspended from the hook partthereof. Specifically,

the switch stick hook is adapted to be received within an upwardlyextending portion 390. of the "loop 39 and to be interlocked with thisportion of the loop during manipulation of the assembly. As best shownin'Figs. 3 and 11 of the drawings, the camrning part 33 of the'pivotelement 35 extends radially outward from the pivot axis of "this elementand is provided with an edge cam surface radially displaced from theaxis of rotation the element. This surface includes-two *d-ilf'ei-entportions 38a and 38b uniformly radiated in each direction from a lowzpoint38c located --nearest1the axis of rotation :of the pivot-element355. These two camming :surface portions 138;: and are selectivelyengageable with the'free leg 25b of the spring 26 to bias the fuse tube88 for swinging movement away from the terminal assembly l-I incident tofuse rupture-regardless of the relative positions occupied by the"terminal assemblies lt and H, i. e. regardless. of

the-one of the two sets of brackets 'II and I2 upon which the insulatorM is mounted. In

mounting the assembly i 5 upon the pivot stud-"25,

the low point 330 of the camming part 38 is movable downward past theleg 26b of the spring '26 without interference. When, however,:the

ement -35 is seated upon the pivot stud 25 and the assembly i5 isrotated toward its closed circuit position, one or the other of the twocam portions 38a and 33b stresses the free end of the spring leg 28btoward the other springleg 26a. In so-doing, the cam part 38 is movedbeneath the main portion of the spring leg 26?) in the mannerillustrated in Fig. 3 of the drawings, thereby to provide a lockbetween-the pivot element 35 and the supporting base 22-whichpreventsremoval of the assembly l5 from the stud25.

For the purpose of positioning the contact parts 54 of the fuseextracting member 45 for latching engagement with the contact elementsof the terminal assembly ll, regardless of the position of this assemblrelative to the'terminal assembly I6, i. e. regardless of whether 'theinsulatori4 is mounted upon the brackets -l l orthe brackets 12,facilities are provided for mounting the pivot end. of-the fuse tube 30upon the pivot element 35 in either of two positions angularly displacedabout the longitudinal axis of the fuse tube. As best shown in Fig. '7of the-drawings, these facilities comprise a conductive ferrule 33fixedly mounted upon the pivot end of the fuse tube 30 and receivablewithin a socket 40 disposed within the socket 3? of the pivot element35. Specifically, the socket 4G is anchored within the socket 3'! of thepivot element by'means of rivets 4!. Along the bottom wall thereof thesocketill fixedly mounts biasing means in the form of a coi1'spring'42,and along its sides is provided with diametrically opposed slots 40b andMic-for receiving lugs or trunnions 34 which extend radialfullprotection for the transformer under any and all overload conditionsimposed thereon, as well as protection against shortcircuiting the linefeeding the transformer should a fault develop-in the transformer, fuselinks of the improved form disclosed and claimed in applicants PatentNo.

2,453,688, dated Nov. 9, 1948, are preferably used in fusing the cutout.After a fuse link-is thus positioned in the bore of the ferrule 33, thisferrule may be positioned to bring the lugs 34 in registry with the slotopenings ebb and 480, following which the neckportion 33a of the ferrule'may be pushed. into the socket 48. As the ferrule end is thus insertedin the socket the lugs 3 are-brought into registry with the. lateral.parts-xof the slots fiiiband dilc: to permit slightrctationzof the fusetube relative to the socket, and thus position the lugs 34 for retentionin the slot seats provided at the ends of the lateral slot parts. Withthe ferrule neck 3311 thus properly positioned within the socket 40, thebiasing spring i2 serves the dual function of forcing the fuse link head3Ia into engagement with the end of the ferrule to maintain goodelectrical contact therebetween and of forcing the lugs 34 intoengagement with the retaining seats of the slots 40?) and 400. Since thelugs 34 are adapted to register with the slots rill) and Mic in eitherof two positions of the fuse tube displaced 180 about the longitudinalaxis of the tube, it will be understood that the tube may be mountedupon the pivot element 35 either in the full line position or the dashline position shown in Fig. 1 of the drawings, thereby to position thecontact parts 54 of the extracting member 35 for engagement with theterminal assembl I? regardless of which of the thereof and separated andformed at 43d clampingly to embrace the fuse tube 33 at a point adjacentthe swing end of the tube. The fuse extracting member :35 is of onepiece construction, preferably being formed from heavy gauge resilientwire stock. It is comprised of supporting parts 55 disposed uponopposite sides of the supporting arm i3 and provided with eyelet endswhich pivotally embrace a short pivot shaft extending through the arm 3at a point intermediate the ends of this aim. The extracting memberfurther comprises contacting and biasing parts 54 in the form of twosets of spring convolutions 5 3a and 5th, and a swingable arm part 53having parallel portions 53a and 532). This arm part is provided at itsswing end 5| with a notch 52 adapted to seat the fuse conductor 32extending from a fuse link 3i located within the fuse tube.

In order to fixedly anchor the extended end of the fuse conductor 32 tothe arm part 53, a clamping assembly is provided which comprises a plate56 having its ends wrapped around and clamped to the spaced arm portions53a and 531), a stud bolt a extending through the plate to between thetwo identified arm portions and fixedly anchored to the plate, a wingnut 56b and a clamping plate 43 adapted to be moved toward the plate 56to clamp the fuse conductor against the plate 56b b threading the nut 5%along the bolt 56a. As best shown in Fig. 12 of the drawings, theclamping plate :36 is provided with overhanging ears Mia and 46b adaptedto project downwardly over the ends of the plate 56 to retain the fuseconductor therebetween. The clamping plate is also provided with endears 45c and 46d displaced longitudinally of the arm part 53 and adaptedto project downwardly over the sides of the plate 58. With this novelconstruction, the four ears 16a, 4131), 45c and 46d serve to preventrelativ rotation between the plates 46 and 56 during a fuse conductorclamping operation, and the ear 46c farthest removed from the swing end5| of the arm part 53 acts as a post around which the fuse conductor maybe looped to provide an effective anchor point for the conductor whichprevents slippage of the conductor between the two plates 46 and 5B.

As indicated above, the convolutions 54a and 541) are employed for thedual purpose of biasing the arm part 53 for swinging movement away fromthe swing end of the fuse tube upon fuse rupture and of engaging thecontact elements of the terminal assembly IT to complete the electricalcircuit between this assembly and the stud 18. In order to limit pivotalmovement of the supporting parts 55 about the stud 43a as the arm part53 is moved toward the swing end of the tube 30, thereb to energize thespring convolutions 54a and 54b, the strips 430, and 43b forming thesupporting arm 43 are respectively provided with oppositely disposedL--shaped lugs 4i and 48 formed integral therewith and having horizontallegs overhanging the spring convolutions. To prevent overthrow of theextracting arm 33 during fuse extracting movement thereof, stop meanscomprising a stud mounted upon projecting portions 50 of the supportingarm parts 43a and 43b within the coil convolutions 54a and 542) areprovided. This stud is adapted to be engaged by the spring convolutionsat the inner sides thereof to provide the desired limit on reverserotation of the arm 53 during its fuse extracting movement.

As explained below, during extracting movement of the arm 53, theportion thereof nearest the spring convolutions engages the contactshoulder iii, for example, to pivot the member 45 about the stud 43c andassist in effecting disengagement of the convolutions and contactshoulder. Direct engagement between the described arm portion and theshoulder 82 is prevented by providing a wear plate 5? adjacent theconvolutions 5 1 having its ends clampingly embracing the arm portions53c and 53b.

As best shown in Fig. 8 of the drawings, the stationary terminalassembly il comprises a conductive L member 52 having a base leg 5%rigidly mounted upon the projecting end of the conductor 58 andpartially supported by an insulating disc 58a resting upon the top ofthe insulator H. The vertical leg Eta of the L member 59 is employed tosupport the remaining components of the terminal assembly. Thesecomponents comprise a main contact element 68 of U-shaped constructionhaving inner and outer lamination 60a and 6%. At the respective leg endsthereof, the outer spring leg thereof is provided with inwardly directedangularly extending shoulder portions 62 and 63, adapted for alternativeuse in contacting the spring convolutions 54 at the outer circumferencethereof depending upon which Of the two sets of supporting brackets IIand I2 is employed to support the insulator M. The described contactelement 653 is adapted to be fixedl mounted upon the vertical leg 59a ofthe L member 59 by means of assembly screws 64 passing through openings{i la in the contact parts 60a and 86b and threaded into openings 64b inthe leg 59a of the member The terminal assembly I? further comprises asecondary contact element 65 of generally L-shaped configuration, havinga vertical leg adapted to be clamped against the back side of the leg59a, and also provided with a horizontally extending leg 65b terminatingin an inturned portion 650 which overhangs the contact element as. Theassembly [7 also includes a combination clamping and terminalsub-assembly comprising a clamping plate 66 having oppositely extendingthreaded portions 66a and 66b, the first of which is adapted which theinsulator I4 is mounted. .pivot element 35 has thus been appropriatelyto be threaded into an Opening Etc through the upstanding leg 55a of themember 59, thereby to clamp the vertical leg 55a of the contact elementfiragainst the leg 5%. The oppositely extending threaded portionfifib ofthe member 63, together with-aclamping element 61 and a nut are employedin making line wire connections to the contact assembly.

As will be evident from the above explanation, one of the two shoulders62 and 63 of the contact elementlii! is cooperable with the springconvolutions 54 to provideself-biased engagement therebetween along asubstantially vertical line. The contact element 65, on the other hand,is cooperable with the base leg 5% to provide electrically conductivecontacting surfaces between the springvconvolutions and the assembl Illin substantially horizontal planes. More specificaliy, the base leg 5%and the contact element are :provided with outwardly flaring camrning Asurfaces 590 and having the function of squeezing the springconvolutions together as these .convolutions are moved into engagementwith the contacting parts of the assembly If. Thus, spring pressedcontacting surfaces are provided between the contact elements of theassembly .I! and the member 45 in planes displaced fIO1l1.6aCh other by90. As a result, vibration which-may be imparted to the parts of thetransformer 6d. cannotproduce chattering engagement of theconvolutions54 with the parts of the contact assembly I7.

Fromtheabove explanation it will be apparent that with the fuse tubeassembly l5 detached from the stationary terminal assemblies IE; and I1,themember 45 is, within the limits permitted by the lugs .41. and 48 andthe stop stud 43, freely rotatable relative to the supporting arm 43.

:When his desired to fuse the assembly I5, the

fuse tube 33 and associated ferrule 33 are detached from the socket 4band a fuse link 3I inserted within the chamber of the tube 33 andferrule 33 so that the pigtail conductor 32 thereof projects out of theopen swing end of the tube. The .neck-portion33a of the ferrule 33 maynow be reinserted into the socket 4b to bring the lugs 34 into seatingengagement with the seats provided at the bottoms of the .slots 42b and40c. .At this point, it will be understood that the angularposition ofthe tube 35] relative to the socket 49 and-pivot element 35 isdetermined by the direction in which the supporting and extracting arms43 and 53 must project laterally in order that the spring convolutions54 may be engageable with the stationary contact assembly I1. This, inturn, is determined by the particular set of supporting brackets II orI2 upon After the mounted upon the ferrule 33 to establish the desiredangular relationship between the pivot bore 36a and the arms 439.112153, the extracting arm 43 is pivoted to bring the swing end5 lthere- -of into engagement with the swing end of the tube 30.

During such initial movement of the arm53 toward the arm 43, thesupporting parts 55 engage the stop l-ugs'4'l such that the springconvolutions 54 are energized as the end 5! of the arm 53 is movedapproximately from the position shown in Fig. 2 of the drawings intoengagement with the swing end of the tube 30.

passed beneath the remaining ear 46a or 46b to extend back toward theend 5I of the arm 53.- After drawing the conductor taut around the ear430, the wing nut 56b is tightened to clamp the conductor 32 between thetwo plates 46 and 53. Thus, the pigtail conductor 32 is tensioned andthe spring convolutions 54 are fully ener gized to effect extraction ofthe conductor 32 incident to rupture of the link 3i.

In order to mount the fuse tube assembly I5 upon the terminal assemblyI6, the hook of aswitch stick is first inserted through the loop 39 tobring the shank portion of the hook into registry with the loop portion39a of reduced diameter. Interlocking of thehook shank with the sides ofthe small diameter opening 39a serve to prevent inadvertent removal ofthe assembly 55 from the end of the. switch stick. To engage the .pivotelement 35 with the contact terminal stud 25, the assembly I 5 ispositioned to bring the low point 380 of the camming part 38 oppositethe leg 26b of the biasing spring 26 and to position the pivot bore 36aover the stud 25. The assembly may now be lowered to engage the pivotelement bore 36a with .the stud 25.

After the assembly I5 is thus pivotallymounted upon the stud 25, thehook of the switch stick may be withdrawn from the loop 39 and engaged.with the arm 43and the tube 30 to rotate the assembly I5 into its closedcircuit position. Assuming that the insulator I4 is mounted upon thebrackets II, the fuse tube assembly I5 is rotated in a clockwisedirection from'the position illustrated inFig. 2 of the drawings tobring the coil convolutions 54 into engagementwith the contact elementsof the contact assembly ll. After the convolutions .54 engage thetapered camming surfaces 590 and 65d, they are squeezed together-as theymove intothe contact assembly. Further, after the convolutions engagethe camming surface of the contact shoulder 52,'the convolutions arepushed to the right from the position shown in Fig. 3 of the drawings toeffect slight clockwise pivotal movement of the supporting parts 55about the pivot shaft 430. Concurrently therewith the leg of the contactelement 6!! terminating in the shoulder I52 is deformed outwardly. Inshort, the deformation of the arm 53 and the contact element 69resulting from engagement of the spring convolutions 54 with the cammingsurface of the shoulder 62, permits the convolutions to pass over thisshoulder as the assembly I5 moves into its closed circuit position.After the high points of the convolutions 54 pass beyond the high pointof the shoulder 52 during the final pivotal movement of the assembly I5,the deformation ofthe parts 6!! and 55 is partially relieved untilfinally the high point of the shoulder 62 bears against the convolutions54 approximately at the points where these convolutions merge into thearm portions 53a and 53b. Engagement of the convolutions with the baseof the contact element 69 prevents the convolutions from moving furtherinto the assembly I'l. Thus a large overhang is provided between theshoulder 82 and the convolutions 54 which positively latches theseelements in engagement. f

As the assembly I5 is pivoted into its closed circuit setting in themanner just explainedthe camming surface 38a of the pivot elementcamming part38rides against the free end of the spring 23b .to flex thisspring end toward the lug 26a of the spring. Thus the parts 25 and .38coact to bias the assembly I 5 for movement of the assembly to its opencircuit position in re sponse to disengagement of the coil convolutions56, from the contact assembly ll. Further, as the camming surface 38aforces the end of the spring leg 26?) away from the axis of rota-- tionof the pivot element 35, the camming part 38 is positioned beneath theupper portion of the spring 26 to provide an interlock which positivelyprevents inadvertent removal of the assembly i5 from the pivot stud 25.

After the fuse tube assembly has thus been operated to its closedcircuit position, a fused current path is provided between the terminalassembly I! and the transformer bushing stud I 8, this path includingthe elements 50, 59 and 65 of the terminal assembly, the extractingmember 45, the conductor 32, the fusible element of the link 3| and themetal housing of the link, the engaged parts 33 and 40, the pivotelement 35 and the parts 25, 22, 2| and I9. In this regard it will benoted that engagement of the spring leg 26b with the cam surface 3811provides pressurized contact surfaces electrically connecting the twoelements 35 and 22. In using the described protective apparatus, theline wire connection is made at the terminal assembly I! by means of theconductor clamping facilities 5'1, 68 provided for this purpose. Alightning surge protective path in parallel with the described fusedpath and the transformer primary winding is provided between theterminal assembly It and the grounded transformer tank. This path includes the conductive rod 58, the spaced electrodes of the arrestor unitMa and the parts Mb and forming the isolating gap M0. The manner inwhich this protective path is rendered conductive when a lightningsurge, for example, appears between the terminal assembly I! and ground,will be readily apparent to those skilled in the art.

So long as current flow over the described conductive path between theterminal assembly I! and the transformer stud l8 does not exceed thecurrent-time fusing characteristic of the link 3|, the fusible elementwithin this link serves mechanically to hold the extracting arm 53 inits set position wherein the end 5| thereof is closely adjacent the openend of the fuse tube 30. When, however, this fusible element is requiredto carry current in excess of a predeter- F mined magnitude for morethan a predetermined time interval, it is ruptured to relieve theholding force imposed upon the extracting arm 53 through the conductor32. The energized coil convolutions 54 now operate rapidly to rotate thearm 53 away from the supporting arm 43, thereby to withdraw the fusepigtail conductor 32 from the open end of the fuse tube 30. In thisregard it is noted that the arm 45 is of substantial length such thatrotation thereof through a relatively small angle produces a largedisplacement between the swing end 5| thereof and the open end of thetube 30. Further, this arm is of small mass and hence has littleinertia, thus insuring rapid acceleration of the swing end 5| thereofaway from the open end of the fuse tube 30. Moreover, the length of theextracting arm 53 and the permissible angle of movement of the arm issuch that under any and all conditions of fuse rupture all of thepigtail conductor 32 and the unfused segment of the fuse link attachedto this conductor are completely removed at high speed from the bore ofthe fuse tube 30 to hang downwardly over the side of the transformertank.

As the arm 45 is rotated from the position illustrated in Fig. 3 to theposition illustrated in Fig. the wear plate 51 comes into engagementwith the shoulder 62 and reacts against this shoulder to pivot the armsupporting parts 55 about the pivot shaft 430 to the position shown inFig. 4 of the drawings. As a result, the coil convolutions are moved tothe right within the contact assembly i? to displace the same out ofoverhanging or latching relationship with the shoulder 62, i. e. to theposition shown in Fig. 4 of the drawings. In other words, and againreferring to Figs. 3 and 4 of the drawings, the path which the leftsides of the convolutions 54 must follow in moving to the open circuitposition is shifted from the are A to the are 13 each having the axis ofrotation of the assembly 15 as its center. It will be noted that thelatter line clears the high point of the shoulder 62, which means thatthe convolutions 5 1 may be disengaged from the contact assembly iiwithout interference by the contact shoulder 52.

Engagement of the wear plate 51 with the camming surface of the shoulder62 also has the effect of producing a component of force acting alongthe arm 53 tending to move the spring convolutions 5Q away from thecontact assembly l'i. This force component is assisted by the spring 25ccacting with the cammin surface 38a. In combination, the two forcecomponents pivot the fuse tube assembly l5 about the terminal stud 25 toefiect the desired disengagement of the spring convolutions 54 from theterminal assembly I1. Following such disengagement, the assembly I5 isswung to its open circuit position about the pivot terminal stud 25under the influence of the spring 26 reacting against the cammingsurface 38a. It will be understood that the open circuit position of theassembly is reached when the end of the spring 251) is brought to bearagainst the low point 330 of the cam part 38.

After the convolutions 54 are disengaged from the terminal assembly I T,the arm 53 rapidly continues its pivotal movement away from thesupporting arm 43 and arm supporting parts 55 continue their pivotalmovement in a clockwise direction about the pivot stud 43c. Pivotalmovement of the latter parts is arrested when the stop stud 49 isengaged by the convolutions 54 at the inner sides thereof. The finalopen circuit position of the member 55 is reached when the parts thereofare moved to the positions shown in Fig. 5 of the drawings.

From the preceding explanation it will be understood that since thedescribed engagement of the plate 5'! with the contact shoulder 62serves primarily to shift the position of the coil convolutions withinthe terminal assembly I! by pivoting the entire member 45 about the studQ30, and further, since the plate 5'! is located relatively close to thecenter of the convolutions 54, the rapid swinging movement of the arm toextract the conductor 32 is not substantially impeded or slowed downthrough engagement of the plate 5'! with the shoulder 62. Further, theimpacting engagement of the plate 57 with the shoulder 52 has the effectof breaking any ice coatings which may have formed on the coilconvolutions 54 and the parts of the terminal as sembly I'I. Moreover,and due to the lever long arm through which the extracting arm 53, inreacting against the contact shoulder 62, exerts a pivoting force uponthe entire fuse tube assembly tending to rotate the same about theterminal stud 25, ice coatings whlch may have formed iuponthepivotelement 35 and the partsof' the assembly it are readily broken. Thus,the described arrangement is such that a secondary break in the fusedconductive path normally extending through the terminal assembly l1 andthe terminal stud l8 is insured, even under severe operating conditions.

in. order to provide for a disconnecting break in the transformerprimarycircuit of. substantial magnitude when the insulator I 4 issupporte'dby the brackets H, the base plate 22 of the assembly I6 isnormally adjusted about the axis of rotation of the pivot element 35, i.e. theJnec'kZIb of the stud 2|, to the approximate position shownin Fig.2 of the drawings. .In adapting the apparatus for support of theinsulator from the brackets i2 in the manner shown :in dash lines inFig. l of the drawings,

the insulator It is pivoted within the clamping half collarsllic and iito a position wherein the contact'shoulder 63 of the contact element 60is adapted to perform the latching andcontacting functions describedabove, rather than the contact shoulder 62. Furthenithe fuse tube 30 andthe parts carried thereby, are rotated through an angle of1'80relative'to thepivot element 35 about the longitudinal axis of the fusetube in a manner clearly apparent from the above explanation.'Afurtherad'justment which is required, is that of pivoting the base22through an' angle*ofapproximatelyilm in a clockwise direction fromtheposition shown in Fig. 2 of the drawings in order to position thespring le Zlb forsenga'gement with thecamming surface 382) of thepivotelement camming part'38. This may conveniently be done by looseningthe screws 24 .etorelieve the clamping force exerted by thehalffcollari-ziib againstthe flared neck 21b of the.stud"2l, and.thenre-tightening these screws after the. base 22 is pivoted to thedesired angularl-pos'ition.

, :After the "described changes are made, the apparatus is arrangedtoioperate in substantially the-exact manner explained above, with theex- .ceptlon that during. open circuit movement of the'aassernbly' l5inresponse to fuse rupture, the assembly :is pivoted in a clockwisedirection, ratherfthanacounter-clockwise direction, due :to's-thereaction betweenthe'extracting arm' 53 and the contact shoulder 63accompaniedby the action .ofithes'springi in reacting against thecamming surface 38b. Regardless of which set ofibrackets II and i2 isemployed to support the insulator-.14, suitable lateral and verticaladjustments in therposition'of the insulator will be required :inorder-accurately to position the contacttassembly i1 relative to thepath'of movesmentof the spring convolutionsli l. This may easilyscbeaccomplishedin an obvious manner by adjustment of the bracket 69relative to the brackets l I or l2 in use and by vertically adjustingrthe bracket Hialong the base legGSb of the bracket 69.

"While" there has 'beendescribed what is at presenti considered to bethe preferred-embodiment of-the invention, it will be understood thatvari :ious modifications may be made therein which. are

:mithin the true spirit and scope of the invention as defined in theappended-claims.

.1. Electrical: protective apparatus, comprising a lpair of spacedterminals insulated from each other and adapted .-to be'supported ineither of two' -differentrelative positions,an expulsion fuse tubeassembly comprising a fuse tube having a pivot end and provided withai'swing end contact latchingly :engageable with one. of said terminals,and means forpivotally supporting said fuse tube at the pivot endthereof :upon the. other of said terminals ineither of two positionsangularly displaced about the longitudinal axis of said fuse tube,whereby said contact'may be positioned for latchingiengagementwith saidone terminal regardless of the. relative positions of said terminals.

2. Electrical protective apparatus, comprising a pair of spacedterminalsinsulated from each other and adapted to be supported inveither :of two different relative positions, an expulsion fuse tubeassembly comprisinga fuse tube havin a pivot. end and provided with aswing end contact latchingly engageable with one of said. terminals,means for pivotally supporting said fuse tube at the pivot end thereofupon the otherof said terminals in either of :two positions angularlydisplaced about the longitudinal. axisof said fuse tube, whereby saidlcontact' may be positioned for latching engagement with saidsoneterminal regardless of the'relative positions of said terminals, fusecontrolled'means for effecting disengagement of saidcontactandoneterminal in response to fuse'rupture withinsaid tube, andbiasing means for pivotingsaid tube about its pivot-end in either of twodirections, thereby to provide for swinging movement of' said'contactaway ifrom said one terminal regardless-of the relative positions ofsaid terminals.

.3. Electrical protective-apparatus, comprising first and secondterminals insulated from each other, means for inounting saidrfirstterminal in either of two positions relative to said second terminal, afuse tube assembly comprising a fuse tube having a pivot end andprovided with a swing endcontact latchingly engageablewith said firstterminal, and-means for pivotallysupporting said fuse tube'at thepiVOtend-thereof upon said second .ter-minalin either of two positionsangularly displaced-about the *longitudinal axis of said fusetubewhereby said contact may be positioned for latching engagement withsaid first terminal regardless of the position-ofsaidfirst terminalrelativeto said second terminal.

4. Electrical protective apparatus,-comprising first andsecondstermina'ls' insulated from each other, means for mounting saidfirst terminal in either of two positions relative to said secondterminal, a fuse tubeassembly comprising a fuse tube having apivotendand provided with a swing end contact latchingly engageable withsaid first terminalgrneans for pivotally supporting said fuse tubeat thepivot'end thereof upon said second terminal in either of two positionsangularly displaced about the longitudinal axis of-said fuse tube,whereby said contact may be positioned for latching engagement with saidfirst terminal regardless of the'positionof said first terminalrelative'to said second terminaL'fuse controlled means for effectingdisengagement of said contact andfirst terminal in response to fuserupture within said fuse tube, and adjustable means for biasing saidfuse tube for pivotal movement in either of two directions to a positionwherein said contact is disposed between said two positions of saidfirst terminal, thereby to provide for swinging movement of said contactaway from said first terminal-regardless of the position occupied bysaid first terminal.

5. Electrical protective apparatus, comprising a pair of spacedterminals insulated fromcach other and adapted to be'suppo'rted ineitherof two different relative positions, an expulsion fuse tubeassembly comprising a fuse tube having a pivot end and provided with aswing end contact latchingly engageable with one of said terminals. apivot element pivotally supported by the other of said terminals, andmeans for detachably connecting the pivot end of said tube to said pivotelement in either of two positions angularly displaced about thelongitudinal axis of said fuse tube, whereby said contact may bepositioned for latching engagement with said one terminal regardless ofthe relative positions of said terminals.

6, Electrical protective apparatus, comprising a pair of spacedterminals insulated from each other and adapted to be supported ineither of two different relative positions, an expulsion fuse tubeassembly comprising a fuse tube having a pivot end and provided with aswing end contact latchingly engageable with one of said terminals, aferrule mounted upon said pivot end of said fuse tube and provided withradially extending locking lugs, a pivot element adapted for detachablepivotal support by the other of said terminals and provided with asocket for receiving the end of said ferrule, biasing means within saidsocket for biasing the head of a fuse link against said ferrule, andmeans within said socket cooperable with said lugs and said biasingmeans for detachably locking said ferrule in said socket in either oftwo positions angularly displaced about the longitudinal axis of saidfuse tube, whereby said tube may be rotated about its longitudinal axisto position said contact for latching engagement with said one terminalregardless of the relative positions of said terminals.

'7. Electrical protective apparatus, comprising a pair of spacedterminals insulated from each other and adapted to be supported ineither of two different relative positions, an expulsion fuse tubeassembly comprising a fuse tube having a pivot end and provided with aswing end contact latchingly engageable with one of said terminals, apivot element pivotally supported by the other of said terminals andprovided with a cam surface radially displaced from its axis of rotationand having different portions uniformly radiating in each direction froma low point, means for detachably connecting the pivot end of said tubeto said pivot element in either of two positions angu larly displacedabout the longitudinal axis of said fuse tube, whereby said tube may berotated about its longitudinal axis to position said contact forlatching engagement with said one terminal regardless of the relativepositions of said terminals, fuse controlled means for effectingdisengagement of said contact and one terminal in response to fuserupture within said tube, and biasing means adjustable about the axis ofrotation of said pivot element for selective engagement with saiddiiferent cam surface portions to pivot said tube in opposite directionsto positions wherein said contact is disengaged from said one terminalregardless of the relative positions of said terminals, thereby toeffect swinging move ment of said contact away from said one terminal inresponse to disengagement therefrom.

8. Electrical protective apparatus, comprising a pair of spacedterminals insulated from each other and adapted to be supported ineither of two different relative positions, an expulsion fuse tubeassembly comprising a fuse tube having a pivot end and provided with aswing end contact latchingly engageable with one of said terminals, aferrule mounted upon said pivot end of said fuse tube and provided withradially extending locking lugs, a pivot element adapted for detachablepivotal support by the other of said terminals and provided with asocket for receiving the end of said ferrule, said pivot element alsobeing provided with a cam surface radially displaced from its axis ofrotation and having different portions uniformly radiating in eachdirection from a low point, biasing means within said socket for biasingthe head of a fuse link against the end of said ferrule, means withinsaid socket cooperable with said. lugs and said biasing means fordetachably locking said ferrule in said socket in either of twopositions angularly displaced about the longitudinal axis of said fusetube, whereby said tube may be rotated about its longitudinal axis toposition said contact for latching engagement with said one terminalregardless of the relative positions of said terminals, fuse controlledmeans for effecting disengagement of said contact and one terminal inresponse to fuse rupture within said tube, and biasing means adjustableabout the axis of rotation of said pivot element for selectiveengagement with said different cam surface portions to pivot said tubein opposite directions to a position wherein said contact is disengagedfrom one contact terminal regardless of the relative positions of saidcontact terminals, thereby to effect swinging movement of said contactaway from said one terminal in response to disengagement.

9. Apparatus for protecting an electrical device disposed Within ahousing provided with a bushing projecting upwardly therefrom,comprising a lightning arr-estor including an insulating housing, meansfor supporting said arrestor in either of two positions relative to thehousing of said device, terminals respectively supported by said bushingand said insulating housing, an expulsion fuse tube assembly including afuse tube having a. pivot end and provided with a swing end contactlatchingly engageable with one of said terminals, and means pivotallysupporting said assembly at the pivot end thereof upon the other of saidterminals in either of two positions angularly displaced about thelongitudinal axis of said fuse tube, whereby said contact may bepositioned for latching engagement with said one terminal contactregardless of the position in which said arrestor is supported relativeto said housing.

10. Apparatus for protecting an electrical device disposed within ahousing having a pair of supporting brackets spaced apart around thesides thereof and provided with a bushing projecting upwardly th refrom,comprising a lightning arrestor including an insulator, means formounting said arrestor on either of said brackets, terminalsrespectively supported by said bushing and said insulator, a fuse tubeassembly including a fuse tube having a pivot end and provided with aswing end contact latchingly engageable with one of said terminals, andmeans for pivotally supporting said tube at the pivot end thereof uponthe other of said terminals in either of two positions angularlydisplaced about the longitudinal axis of said tube, thereby to positionsaid contact for latching engagement with said one terminal regardlessof the bracket upon which said arrestor is mounted.

11. In apparatus for protecting an electrical device, the means forpivotally supporting a fuse tube and for biasing the fuse tube forswinging movement from a closed circuit position to an open circuitposition, which comprises a terminal,

a pivot element adapted for detachable pivotal support by said terminaland provided with a cam surface radially displaced from its axis ofrotation, biasing means engageable with said cam surface to swing saidtube from its closed circuit position to its open circuit position, andinterlocking means for detachably mounting a fuse tube upon said pivotelement in either of two locked positions angularly displaced about thelongitudinal axis of said fuse tube.

12. In pparatus for protecting an electrical device, the means forpivotally supporting a fuse tube and for biasing the fuse tube forswinging movement from either of two closed circuit positions to an opencircuit position, which comprises a terminal, a pivot element adaptedfor detachable pivotal support by said terminal and provided with a camsurface radially displaced from its axis of rotation and havingdifferent portions uniformly radiating in each direction from a lowpoint, biasing means selectively engageable with said different camportions to pivot said tube 18 respectively from said two closed circuitpositions to open circuit positions, and means for detachably mountingsaid fuse tube upon said pivot element in either of two positionsangularly displaced about the longitudinal axis of the fuse tube.

EDWARD H. YONKERS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

